Archive for January, 2009

Honeybees See the Difference Between Numbers—Literally

By Nina Bai | January 28, 2009 5:38 pm

beeHoneybees have the ability to distinguish and remember visual quantities up to four, according to a new study. Researchers demonstrated that honeybees can match patterns containing the same number of icons, even when the icons are of mixed color and shape. This suggests that honeybees possess a basic number sense that was once thought to be exclusive to vertebrates. Researcher Shaowu Zhang says, “There has been a lot of evidence that vertebrates, such as pigeons, dolphins or monkeys, have some numerical competence but we never expected to find such abilities in insects. So far as these very basic skills go, there is probably no boundary between insects, animals and us” [Daily Mail]

To test the extent of the bees’ number sense, researchers set up a Y-shaped maze with a sweet treat at the end of one arm. In the training phase, bees entered the base of the maze through an entrance marked with either two or three dots. They had to remember this number when the maze forked into two paths— one marked with two dots, the other with three—in order to reach a sugar-water reward [Telegraph]. The 20 or so bees that were trained attained a success rate of 70 percent. Researchers then presented tougher challenges by increasing the number of dots. The bees could also distinguish between three and four dots, but were confused when even more dots were added. 

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Dumping Iron Into the Ocean Might Not Save the Climate, After All

By Eliza Strickland | January 28, 2009 4:36 pm

ocean fertilizationOne of the most controversial geoengineering schemes that has been proposed to slow the course of global warming, ocean fertilization, received mixed reviews from a new study. The idea involves dumping iron into the ocean to nourish plankton and spur enormous blooms, which would then die off and fall to the sea floor, bringing the carbon dioxide they’d absorbed with them. Now, researchers studying natural plankton blooms near Antarctica have new evidence to fuel the debate over the efficacy of the process, and whether or not it can get our planet out of hot water.

Scientists took measurements around the Crozet Islands, where there are naturally occurring fluxes in iron levels. To the north of the islands levels of iron are boosted each year as iron-rich volcanic rocks are eroded and the nutrients are carried off by the current [Times Online]. Researchers observed a huge plankton bloom there that covered an area the size of Ireland and lasted for more than two months, while also studying the water to the south of the islands, where the prevailing ocean currents don’t carry dissolved iron and therefore plankton blooms don’t form naturally. The results, to be published tomorrow in Nature [subscription required], showed that iron-enriched waters do, as hoped, encourage more carbon to be stored on the ocean floor. But the efficiency of artificial iron fertilisation could be as much as 50 times lower than previous estimates [New Scientist].

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Rival Triceratops May Have Locked Horns Like Deer

By Eliza Strickland | January 28, 2009 2:43 pm

Triceratops fightA close examination of over 400 Triceratops skulls suggests that the iconic dinosaurs used their powerful horns to clash with rivals over mates, territory, and dominance. In a new study, researchers looked carefully for traces of scrapes and healed fractures on the fossilized skulls, and say the pattern they found fits the theory that the three-horned herbivores were going head-to-head. “The most likely culprit for all of the wounds on Triceratops frills was the horns of other Triceratops,” [lead researcher Andrew] Farke said. “Our findings provide some of the best evidence to date that Triceratops might have locked horns with each other, wrestling like modern antelope and deer” [Times Online].

The researchers compared the Triceratops skulls to those of another dinosaur called Centrosaurus, which also boasted three horns and a bony protective frill around its face. The two species were related, but Centrosaurus died out about 75 million years ago and had its largest horn on its snout, while Triceratops lasted until 65 million years ago and had more prominent horns over its eyes. With such different horn patterns, the researchers assumed that if the dinosaurs were horn-butting with members of their own species the injuries of Triceratops and Centrosaurus should also be different from each other. But if they weren’t poking and butting one another with those horns, the injuries should be relatively similar, perhaps due to random nicks from clumsily running into a tree or head butts from predators, Farke said [LiveScience].

As the researchers report in the journal PLoS ONE, the Triceratops skulls showed a pattern of old injuries in one specific part of the bony frill that would likely have been impacted if two individuals were banging their heads together, but the Centrosaurus showed no such pattern.

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Emerging Pattern Shows Football Can Cause Devastating Brain Damage

By Eliza Strickland | January 28, 2009 11:11 am

footballThe regular collisions and concussions that take place on the football field may have a cumulative effect on the players’ brains, according to several new studies. In one small study, researchers found that just a few concussions can have an impact on cognitive skills 30 years later, while the other, more dramatic study found that a deceased NFL player was suffering from a severe degenerative brain disease. Taken together, the studies add to the mounting evidence that repeated blows to the head in football games lead to debilitating later-life afflictions such as dementia [Washington Post].

The biopsy of the NFL lineman Tom McHale, who played from 1987 to 1995 and who died last May at the age of 45, was announced at a press conference timed to coincide with the preparations for the Super Bowl this Sunday. The biopsy showed that McHale was suffering from chronic traumatic encephalopathy, researchers said. Known as C.T.E., the progressive condition results from repetitive head trauma and can bring on dementia in people in their 40s or 50s. Using techniques that can be administered only after a patient has died, doctors have identified C.T.E. in all six N.F.L. veterans between ages 36 and 50 who have been tested for the condition, further evidence of the dangers of improperly treated brain trauma in football [The New York Times].

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CATEGORIZED UNDER: Health & Medicine

Can a Google Algorithm Predict Nobel Prize Winners?

By Eliza Strickland | January 28, 2009 9:24 am

Nobel PrizeTrying to assess the importance of particular scientific papers has long been a tricky task. The current system relies on counting the number of times a paper is cited by others to determine how large an effect it has had on subsequent research, but this number can be misleading, a new study notes. Simply counting citations favors disciplines such as biology, where papers tend to be cited more, over fields such as mathematics, where citations are less frequent. In addition, a citation from a relatively marginal paper counts just the same as a citation from a leading researcher publishing in a marquee journal [Scientific American].

To try to get around these problems, a pair of researchers decided on a different tactic: They took the algorithm that Google uses to determine how to rank the Web pages turned up in a search result, and used it to rank the importance of scientific articles. The Google PageRank algorithm checks the number of times each Web page is linked to in order to determine its importance, which is equivalent to counting citations. But it has several other aspects that were very useful when applied to ranking scientific papers. The algorithm gives greater weight to citations from papers that list only a few references, and also to citations from papers that are themselves often cited. “Because of these attributes, PageRank readily identifies a large number of scientific ‘gems’–modestly cited articles that contain ground-breaking results” [arXiv], the researchers write. Among those gems turned up in the researchers first experiment were nine papers written by future Nobel Prize winners.

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CATEGORIZED UNDER: Physics & Math, Technology
MORE ABOUT: arXiv, Google, math, Nobel Prize

Sea Sponge Is Ousted, So What's the Last Common Ancestor of All Animals?

By Nina Bai | January 28, 2009 7:45 am

placozoanA new genetic analysis has shaken up the tree of life, dispelling the common assumption that sea sponges or comb jellies are the original ancestors of all animals. That original animal, also referred to as the “ur-animal,” is thought to have given rise to both the “lower” animals (Cnidaria), such as coral and jellyfish, and “higher” animals (Bilataria), such as insects and humans. Based on the new study, researchers are now putting forth a new classification, which would place sponges among the “lower” animals, leaving an open spot for the original animal. “It’s a question that has plagued animal biologists for a couple hundred years: What could be the mother of all animals?” said [researcher] Rob DeSalle… “We’ve turned it upside down” [Wired Science].

Taxonomy has come a long way since the Linnaean system, based largely on comparative anatomy, was introduced in 1735. The research team fed morphological data on the appearance of animals from 24 taxa together with genetic information into a computer program that assessed similarities and differences to generate a phylogenetic tree of life [Nature News]. The results placed placozoans, a simple amoeba-like but multi-celled organism, as a more ancient animal than even the sea sponges. Yet, at the same time, the data suggests that placozoans is not the last common ancestor of all animals because they are not directly related to the more complex Bilataria. “It fits in with what you might think is the most basal animal. It’s only got three cell layers and four cell types. Its motility is primitive. It lives in warm oceans. It’s got all the earmarks of the thing that gave rise to all animal life,” said DeSalle [of placozoans]. “But that’s not what the results show. And though placozoa is the ur-cousin of complicated life, we still don’t know the ur-mother” [Wired Science].

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"Laser Avenger" Shoots Down Unmanned Plane in a Test of Future Weaponry

By Eliza Strickland | January 27, 2009 6:10 pm

laser avengerIn a preview of possible high-tech battles to come, Boeing has announced the successful test of a laser weapon designed to shoot down unmanned aerial vehicles (UAVs). Robotic spy and combat planes are a hot field of military research because their use doesn’t endanger pilots, and because they can be smaller and harder to detect than conventional planes. But Boeing vice-president Gary Fitzmire argues that the military should be investing not just in UAVs, but also in devices that can destroy them. “Small UAVs armed with explosives or equipped with surveillance sensors are a growing threat on the battlefield,” he insists. “Laser Avenger, unlike a conventional weapon, can fire its laser beam without creating missile exhaust or gun flashes that would reveal its position. As a result, Laser Avenger can neutralize these UAV threats while keeping our troops safe” [The Register].

The weapon was tested at the White Sands Missile Range in New Mexico, where the Laser Avenger tracked three UAVs flying “against a complex background of mountains and desert”, shooting down one of the UAVs [Gizmodo]. The device got its sci-fi tinged name because it’s a modified version of the Army’s existing Avenger air defense system, which had two missile launchers mounted on a Humvee. To build the Laser Avenger, Boeing swapped its ray gun and a target tracker for one of those missile launchers.

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Cutting Calories Drastically Could Boost Senior Citizens' Memory

By Eliza Strickland | January 27, 2009 4:20 pm

saladElderly people who ate one-third fewer calories for three months showed marked improvements on memory tests, according to a small new study that’s just the latest evidence linking caloric restriction to good health. There is growing interest in the potential benefits of calorie restricted diets, after research in animals suggested they might be able to improve lifespan and delay the onset of age-related disease. However, it is still not certain whether this would be the case in humans – and the the levels of “caloric restriction” involved are severe [BBC News].

The study involved 50 elderly people who ranged from normal weight to overweight. Members of one group were asked to cut their daily calorie consumption by 30 percent, primarily by reducing their portions, another group kept their calorie intake the same but ate more of the healthy, unsaturated fats found in fish and olive oil, while a final group made no dietary changes. When the volunteers took memory tests after three months, only the calorie-restriction group showed improvement. Neuroscientist Mark Mattson comments that the study “adds to considerable evidence from animal and human studies that high calorie intake is not only bad for your heart, but it’s bad for your brain” [Technology Review].

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CATEGORIZED UNDER: Health & Medicine

Emperor Penguins May Be Marching to Extinction by 2100

By Eliza Strickland | January 27, 2009 10:17 am

emperor penguinsThe predicted loss of sea ice around Antarctica over the next century may doom one of the celebrities of the animal world to extinction. Emperor penguins, the species of these aquatic flightless birds featured in the Oscar-winning 2005 documentary “March of the Penguins,” breed on Antarctic sea ice and dive from the sea ice to feed on krill, fish and squid [Reuters]. In a new study, researchers examined the Intergovernmental Panel on Climate Change’s (IPCC) projections on how global warming will alter sea ice coverage around Antarctica, and say the models don’t auger well for the emperor penguins.

The researchers combined ten different climate projections with a “population dynamics” model describing the mating patterns and breeding success of emperor penguins. The model has been honed using 43 years’ worth of observations of an emperor colony in Antarctica’s Terre Adelie…. They then ran 1,000 simulations of penguin population growth or decline under each of those 10 climate scenarios [BBC News]. The results predicted that the 6,000 breeding pairs in Terre Adelie could be reduced to 400 pairs by 2100. Researchers say this 95 percent decline qualifies as a “quasi-extinction,” as the colony’s tiny remaining population would be vulnerable to diseases and genetic defects. They also say that the possible demise of the Terre Adelie colony could indicate the fate of the entire species (about 200,000 breeding pairs currently live in 40 colonies around Antarctica).

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CATEGORIZED UNDER: Environment, Living World

Even Newborn Infants Can Feel the Beat

By Eliza Strickland | January 27, 2009 8:55 am

baby musicBabies just a few days old can already identify a rhythmic pattern, and their brains show surprise when the music skips a beat, according to a new study. Researchers played recordings that used high-hat cymbals, snare drums, and bass drums to make a funky little beat while monitoring the infants‘ brain activity with non-invasive electroencephalogram brain scanners, and found that newborns respond to a skipped beat in the same way that adults do.

The ability to follow a beat is called beat induction. Neither chimpanzees nor bonobos — our closest primate relatives — are capable of beat induction, which is considered both a uniquely human trait and a cognitive building block of music. Researchers have debated whether this is inborn or learned during the few first months of life, calibrated by the rocking arms and lullabies of parents [Wired News]. While the researchers who conducted the new study say their findings are evidence that beat induction in innate, others argue that the newborns could have already learned to identify rhythmic patterns by listening to their mothers’ heartbeats while in the womb.

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CATEGORIZED UNDER: Human Origins, Mind & Brain

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